1. Field of the Invention
The present invention relates to an image signal processing apparatus, an image display, and an image display method that perform image processing by using detection results of a black band region included in an image signal.
2. Description of the Related Art
In general, an image display such as a television receiver (TV) includes an image processing function to provide an input image with image quality correction (for example, functions such as luminance or contrast control and contour correction). Such an image processing function is achieved by acquiring, for example, the average peak level (APL) of input image signals or histogram distribution of luminance levels, and is effectively applied, because gradation is improved by preventing an image from appearing too dark or preventing poor reproduction of black.
Further, some of recent TVs include a function to display an image by scaling an input image signal. Then, in scaling the input image signal as above, it is necessary to consider whether a black band region is included in the input image signal. The black band region is included in, for example, an image signal of a DVD (Digital Versatile Disk) recorded in the Cinemascope size or an image signal sent from a broadcast station. As a method thereof, there are a method called letterbox including the black band regions above and below an image region, and a method called side panel including the black band regions on the right and left of an image region. To scale the input image signal including the black band region as above, it is necessary to detect the black band region to prevent the black band region from being displayed on the display screen.
In this regard, to effectively detect the black band region included in the input image signal as above, various methods have been proposed (for example, refer to Japanese Unexamined Patent Application Publication Nos. 2005-203933 and H08-256302, and Japanese Patent No. 2588999).